Abstract
The structure of trilobine had been believed to be I formula. In order to determine the absolute configuration of its asymmetric centers and the position of its secondary nitrogen, trilobine was N-acetylated and N-acetyltrilobine (IV) was submitted to the improved cleavage reaction with sodium-sodium hydride in liquid ammonia. Two-step fission successfully afforded two coclaurine moieties constituting the trilobine molecule. The non-phenolic base afforded 1-(p-methoxybenzyl)-2-methyl-6-methoxy-1, 2, 3, 4-tetrahydroisoquinoline (V), m.p. 58-62°, [α]D20+128.7° (c=0.633, 95% EtOH). Non-basic phenol was O-methylated and gave 1-(p-methoxybenzyl)-2-acetyl-6, 8-dimethoxy-1, 2, 3, 4-tetrahydroisoquinoline (VI), m.p. 137-142°. From these experimental results and the fact that N-methyltrilobine and isotrilobine are identical substances, it became clear that the structure of trilobine would be represented by VII.
